Background and importance Recent studies suggest the use of topical insulin on the ocular surface to accelerate cicatrisation of corneal lesions in diverse ocular pathologies, such as postoperative corneal epithelial erosion, neurotrophic keratitis and refractory corneal ulcers. However, its use has not been extended into real clinical practice.

Aim and objectives To describe an eye drop formulation of insulin 1 UI/mL for use in corneal defects refractory to previous treatment, and to evaluate its possible application in regular practice.

Material and methods A bibliographical search was performed in Pubmed using the following keywords: topical insulin, corneal ulcers and epithelial defects refractory; 9 results were found. Five references were selected with the most recent publication dates (2017–2020).

The pharmacy and ophthalmology departments reached an agreement to compound an eye drop formulation of topical insulin 1 UI/mL. The preparation was carried out in the pharmacy department in a horizontal laminar flow cabin following an aseptic compounding technique using regular insulin (100 UI/mL) and artificial tears with a polyethylene glycol base. The dilution was then filtered and packaged in light protected eye drop bottles. The risk matrix of sterile preparations of the Sociedad Española de Farmacia Hospitalaria was applied obtaining a low level of risk, which established a validity period of 14 days refrigerated or 48 hours at room temperature.

Results The formulation obtained was a transparent sterile liquid, adequate for ocular use. A visual control was performed during the validity period, with no physical alterations of the product. Currently, nine patients with neurotrophic corneal ulcers or epithelial defects, refractory to medical and/or surgical standard treatment, have been treated. Mean number of days of treatment was 21±7 days. Improvement in pain was observed in every patient and total healing of the lesion was reported in 66% of patients. No adverse reactions were reported.

Conclusion and relevance Compounded topical insulin was adequate for ocular use, with no alterations during the validity period. Acceptance by patients was good, achieving quick relief of pain in every patient and total healing of the cornea in most patients. This preparation can be used as a treatment option in corneal defects refractory to previous treatment.

Conflict of interest No conflict of interest